Specifications

TD 92326GB
2009-03-10 / Ver. E
Installation and Operation Manual
VoIP Gateway
29
3 Click “OK”.
6.2 NAT – Network Address Translation
Note: Not supported by Ascom. See 3.3 Configuration Information on page 10.
Enables a local area network (LAN) to use one set of IP addresses for internal traffic and a
second set of addresses for external traffic. A NAT box located where the LAN meets the
Internet makes all necessary IP address translations.
NAT serves three main purposes:
• Provides a type of firewall by hiding internal IP addresses.
• Enables a company to use more internal IP addresses. Since they are used internally
only, there is no conflict with IP addresses used by other companies and organizations.
• Allows a company to combine multiple ISDN connections into a single Internet
connection
1 Select IP > NAT.
Figure 24. NAT
2 Enable/Enter following settings.
Private Networks: By indication of a private network the VoIP Gateway can steer
the Media Relay function. Both signalling (and RTP stream for
VoIP calls that are routed into non-private networks by the
VoIP Gateway) will flow through the VoIP Gateway.
All networks are considered private if none is configured.
Without Media Relay function the RTP packets are exchanged
directly between the endpoints.
A list of private networks can be specified.
•
•
Address
Mask
Enter the IP address and network mask to the private network
Figure 24.
Field name Description
• Enable NAT Activates the NAT module.
NAT only needs to be active on networks requiring
official IP addresses and is not required if the connection
is operated with unofficial, but known, IP addresses. See
B.1 NAT and Firewalls on page 165.
• Default forward
destination
IP address of the host that inbound requests are sent to.
Not recommended. We recommend the Port specific
settings below.
Port specific forwardings: A list of protocol and port specific hosts that inbound
requests are sent to, can be set.